Drill bit



Maldl 1940; L. L. SANDERS ET AL 2,194,675

DRILL BIT r11 April-5, s srie'ps-gpeet 1 M r h 26,1940 1. L. SANDERS Em 2 194,615

mum. BIT

Filed April 5, 1937 6 Shpets-Sheet 2 March 26, 1940. L. SANDERS r AL I 2,194,675

'[DRILL BIT mu A a-15., 193v s Sheets-Sheet a Patented Mar. 26, 1940 PATENT borne]:

DRILL BIT Leon L. Sanders and George C. Street, Fort Worth, Ten, assignors of ten per cent to David C. Vance, Fort Worth, Tex.

Application April 5, 1937, Serial .No. 134,977

7 Claims.

This invention relates to new and useful improvements in drill bits.

One object of the invention is to provide an improved drill bit particularly adapted for use 8 in the drilling of wells and having improved means for mounting the cutters on the bit body.

An important object of the invention is to provide an improved drill bit wherein a plurality of elongate rollers having rounded ends are in- 10 terposed between the cutter and the axle on which said cutter is mounted, said rollers not only securing said cutter on said axle, but also acting to take the bearing thrust whether suchthrust be longitudinal or transverse of the axle. 35 Another object of the invention is to provide a plurality of improved rollers for fastening the cutter to the axle of thebit body, which rollers may be inserted after the cutter is in place on the body, there being means for holding the 90 rollers in their proper, position to permit the cutter to rotate to perform the cutting operation.

Still another object of the invention is to provide an improved drill bit having its cutters rotatably mounted on an axle,'with elongate 25 rollers having rounded ends interposed between the axle and upper end of the cutter and also having tapered rollers interposed between the lower end of said axle and cutter, whereby added bearing thrust longitudinally of the axleis pro- 30 cured; the provision of the tapered rollers further providing a comparatively large diameterbearing nearer the point of the cutter to support said point which increases the drilling efliciency.

A still further object of the invention is to 85 provide an improved drill bit of the character described wherein the lower end or point of the cutter may be supported by a frictional bearing bushing or collar, whereby construction costs are reduced to a minimum.

40 Still another object of the invention is to provide an improved drill bit including cutters which are fastened to their axles by elongate rollers having flat ends, and wherein a floating bushingsupports the point of each cutter on its 45 axle, together with improved means for lubricating the bearing surfaces, whereby the life of the bearing members is increased.

A further object of the invention is to provide an improved drill bit wherein the cutter shafts 50 are detachably secured-to the bit body in an improved manner, which permits the bit to be repaired, or parts thereof, readily replaced; the detachable mounting of said axle making it possible to heat-treat theaxles alone instead of a the entire body, as is the case when the axles are integral with the body, therebyresulting in decreased manufacturing costs.

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, in which an example of the invention is shown, and wherein:

Figure l is a view, partly in section and partly in elevation of a drill bit, constructed in accordance with the invention,

Figure 2 is a transverse, sectional view, taken on the line 2-2 of Figure 1,

Figure 3 is a perspective view of the retaining p Figure 4 is an enlarged, vertical, sectional view taken through the cutter and shaft and showing a slightly modified form of the invention, 50

Figure 5 is a transverse,.sectional view, taken on the line 5-5 of Figure 4,

Figure 6 is a similar view, taken on the line 6-6 of Figure 4,

Figure 7 is a view similar to Figure 4 of another 95 form of the invention,

Figure 8 is a transverse, sectional view, taken on the line 8-8 of Figure 7,

Figure 9 is a similar view, taken on the line 9-9 of Figure 7,

FigurelO is a view, similar to Figures 4 and 7, and showing another modification of the invention,

Figure 11 is a transverse, sectional view, taken on the line ll-I I of Figure 10,

Figure 12 is a transverse, sectional view, taken on the line "-42 of Figure 10,

Figure 13 is a perspective view of the retaining Figure 14 is an end elevation of still another form of the invention,

Figure 15 is a view partly in elevation and partly in section and showing the mounting of the axle on the body,

Figure 16 is a sectional view, taken on the line lG-IG of Figure 15,

Figure 17 is an' elevation of one half of the bit i body and showing the axle detached therefrom,

said axle being in section,

Figure 18 is a longitudinal sectional view of the cutter, and V Figure 19 is a perspective view of the bit body. In the drawings, the numeral Ill designates a split body having an externally threaded pin II at its upper end whereby the body may be connected to the lower end of a drill stem (not shown). The body is formed with a pair of depending legs or wings I2 which are located diametrically opposite each other on the body. The legs are preferably made integral with the body and have their outer surfaces substantially vertical, while their inner faces I3 are fiat and incline upwardly toward the center of said body. These inner faces of the legs merge, as is clearly shown in Figure 1.

Each leg I2 has a cutter shaft or axle I4 extending inwardly and downwardly from the inner face I3 thereof. Since the construction of each axle and the cutter mounted thereon are exactly alike, a description of one will suiiice.

Each axle I4 is preferably integral with the leg l2 and has its outer end reduced at I5, whereby an annular offset or shoulder I6 is formed thereon. A conical cutter I! having external cutting teeth I8 has an axial opening. or bore I9 which extends inwardly from the upper side of the cutter, terminating near the point of said cutter. This bore has its inner end reduced at 20 whereby an annular shoulder 2| is formed, and obviously the cutter is arranged to be mounted on the axle with said axle engaging the bore. The diameter of the bore and its reduced portion is larger than the diameter of the axle and its reduced end I5,

so that there is a clearance between the cutter and axle when said cutter is in position. Also, there is a clearance between the shoulder I6 on the axle and the shoulder 2| within the bore.

For rotatably securing the cutter I! on the axle, said axle is formed with an annular groove or recess 2| at its upper end. This recess is elongate and has its end rounded at 22' as clearly shown in Figure 1. A complementary recess or groove 22 is formed in the wall of the bore I9 of the cutter and a plurality of retaining rollers 23 are mounted in the raceway formed by the'recesses 2| and 22. The rollers are an important feature of the invention and are elongate with rounded ends 23'. The rounded ends of each roller abut the rounded ends ofthe recesses 2| and 22 and act as ball bearings to take the thrust longitudinally of the shaft. The elongate rollers of course, bear the transverse thrust. Therefore, it is manifest that a roller constructed in this manner provides the advantages of the usual roller bearing and the ordinary ball bearing.

For inserting the rollers 23 into the raceway formed between the axle and cutter, a circular opening 24 (Figure 2) is provided above the raceway. This opening is formed by cutting a semicircular recess 24a in the top of the cutter, and by cutting a similar recess 24b in the axle l4. When alined as in Figure 2, the recesses form the opening 24, which permits the rollers 23 to be inserted into the raceway. An inclined opening 25 extends upwardly from the opening 24 through the leg I2 of the body whereby the rollers may be inserted therethrough.

For closing the opening 24 to prevent upward displacement of the rollers 23, a semi-circular plug 26 is adapted to be welded or otherwise secured in the recess 24a in the cutter. This plug has no connection with the axle and therefore,

the cutter is free to rotate thereon. For closing the recess 24b in the axle, a retaining pin 21 is insertable in the opening 25 of the leg 2. This pin is clearly shown in Figure 3 and has a lug or extension 28 semi-circular in cross-section on its inner end. This lug is adapted to engage within the recess 24b in the axle above the raceway, and its lower end is curved complementary to the rounded end of the rollers 23. The pin may be welded or otherwise secured in the opening 25 and manifestly, said pin together with the plug 26, retains the rollers within the raceway formed by the grooves 2| and 22. The pin is stationary being a part of the axle while the plug 26 becomes a part of the cutter I1 and rotates therewith.

For supporting the point of the cutter IT, a bearing raceway 29 is formed between the reduced inner end of the-bore I9 and the reduced end I5 of the axle. A plurality of rollers 30 are mounted in this raceway and rotatably support the point of the cutter. It is noted that the raceway has been formed by providing an annular recess 29' in the axle with no recessing of the wall of the bore. The rollers are inserted into the grooves and the cutter then slipped over the axle causing said rollers to enter the reduced end of the bore. The rollers 3|! shown in Figure 1 have fiat ends and are of the same diameter throughout their lengths. The thrust transversely of the axle I4 is of course, borne by these rollers.

From the above, it will be seen that an improved mounting for the cutter I1 is provided. The use of ball bearings, together with their inherent disadvantages, is eliminated. The rounded ends 23' of the rollers 23 however, give all of the advantages of the ball bearing and in effect each elongate bearing 23 is a combination roller and ball hearing. The structure is such that assembly or disassembly is simplified, there being only the pin 21 and plug 26 to be removed or inserted. The axle or shaft I6 is not materially weakened, there being only the recesses or grooves 22' and 29 therein. The rollers 23 not only provide bearings for carrying the longitudinal and transverse thrust but also act as a means for retaining the cutter on the shaft.

As above disclosed, the point of each cutter I1 is supported by the rollers 30 which have flat ends. These rollers bear the transverse thrust but due to their fiat ends do not take any of the thrust longitudinally of the shaft. This is true because the longitudinal thrust will bind the flat ends of the rollers against the end walls of the raceway or recess 29, thereby creating a drag which impedes rotation of the cutter. Therefore, although the rollers 30 may be employed successfully in many instances there are cases where the excessive longitudinal thrust on the cutter point which would render the use of the rollers 30 undesirable.

Under such conditions, the structure shown in Figures 4 to 6 would be preferable. In this structure, the reduced end I5 of the axle is tapered or conical instead of cylindrical. The complimentary portion of the bore 20 is also tapered so as to receive said reduced end. An annular recess or groove 3| is formed in the surface of the reduced end I5 and a plurality of tapered rollers 32 are adapted to be received therein. These rollers also engage the wall of the tapered bore 20' and rotatably support the point of the cutter. Manifestly, the tapered rollers not only bear a transverse thrust, but also take any thrust longitudinally of the axle I4 due to their tapered surface. By employing the tapered rollers, the bearing members may be located nearer the point of the cutter without materially reducing the size of said members. Also, the tapered rollers do not have a tendency to bind as do the rollers having the same diameter throughout their length.

As above explained, there are instances in which a substantially great longitudinal thrust occurs during the drilling operation; similarly, there are instances where the longitudinal thrust is negligible with an increased transverse thrust. In such cases, it is desirable to provides. bearing at the point of the cutter which will efficiently take this transverse thrust. Such a structure is shown in Figures '7 to 9. In this form of the invention the axle i4 is constructed substantially the same as in Figure 1 except that the annular groove 29' in the reduced end I5 of the axle is eliminated.

The rollers 23 of Figure 1 are employed and mounted in the same manner but therollers 30 are omitted. In place of these latter rollers, a

bearing collar 33 surrounds the reduced end l5 of the axle and is rotatable thereon. The outer surface of the collar of course, engages the wall of the reduced'portion of the bore l9, and obviously, this collar rotatably supports the point of the cutter and bears the transverse thrust.

For aiding the rollers 23 in taking the thrust i0 longitudinally of the shaft if such thrust occurs,

a raceway 34 may be provided at the shoulder It on the axle. This raceway is formed by recessing the surface of the axle l4 and the wall of the cutter bore and a plurality of ball bearings 35 are 86 confined in said raceway. In some instances, it

would be possible to eliminate the balls 35 and raceway 34; whereby the longitudinal thrust would be borne by the rounded ends of the rollers 23.

80 For lubricating the bearing members 23, 33 and 35 of this form (Figure 7 an elongate passage 36 extends through the leg I! of the bit body and axially through the axle l 4. A plug 31 is arranged to close the upper end of this passage- A suit- 85 able lubricant may be introduced into the passage and will pass downwardly to the inner end of the bore of the cutter. The lubricant will then pass upwardly between the axle l4 and bore l9 "to'lubricate the collar 33, ball bearings 35 and rollers 23. To prevent escape of the lubricant from the upper end of the bore of the cutter, the axle is formed with an annular packing groove 38 which is located above the recess 2| for the rollers 23. This groove receives an annular elastic I packing ring 39 which has its outer edge engaging the upper end of the cutter bore, whereby the annular clearance between the cutter l I and axle I4 is sealed oil to prevent escape of the lubricant when the cutter is rotating. It is evident that 50 by confining the lubricant within the bore, the bearing members are lubricated at all times which not only makefor more efiicient operation of the cutters but also increases the life of the bearing members. It is pointed out that this method of lubricating the bearing members is not to be limited to the structure shown in Figures 7 to 9, but may be applied to any of the forms shown herein.

In Figures 10 to 13, the lubricating means is shown as applied to a modified form of the invention. In this form, the axle I4 is provided with elongate recesses 2| while the wall of the cutter bore H! has complementary recesses l9. Elongate rollers 40 are adapted to fit in the race- 55 way formed by these recesses. It is noted that the rollers 43 have flat ends instead of rounded ends as the rollers 23. The bearing collar 33 surrounds the reduced lower end l5 of the axle and the ball bearings 35 and raceway 34 shown in Fig- 70 ures 7 to 9 are omitted. The packing ring 39 in this form is inserted in annular grooves 38 which are formed in the top of the cutter l1 and in the flat surface l3 of each leg l2. Manifestly the collar 33 and rollers 40 are the only bearing ll members and act to carry transverse thrust. This of the other forms.

structure is simple in construction and cheap to manufacture and is adapted for use where longitudinal thrust on the cutter is negligible.

In Figures 14 to 19, another form of drill bit is shown. It is many times desirable to replace the i cutters I! in the field and therefore, to make for easy replacement of the cutters, the axle on which said cutters are mounted may be made removable from the legs l2 of the body. ,such a structure is shown in'Figures 14 to 19 and in this structure the mounting of each cutter I! on its axle I4 is exactly the same as that shown in Figures 4 to 6, the elongate rounded end rollers 23 and tapered rollers 32 being employed. Instead of making each axle l4 integral with the leg l2 as in the other forms. said axle is made separate therefrom and is provided with an integral block or body portion 45 at its upper end which-is adapted to be secured to the leg l2 of the bit body. The block is formed with a longitudinal groove 43 20 which is T-shaped in cross-section (Figure 16). The groove extends throughout the length of the block and is adapted to receive a T-shaped lug 4 1 which depends from the inner surface of each leg l2 of the body l0 (Figure 19). It is noted 25 that in this form the leg I! is comparatively narrow in transverse vertical section, whereby the leg is narrower than the bodylll'. In the other forms herein disclosed the outer vertical surfaces of the leg I2 form a'continuation of the body merging into the surface thereof.

When the block 45 which has the axle H integral therewith is slid upwardly with the lug 41 engaged with the groove 46, the outer surfaces of the block form a continuation of the body It), whereby the leg l2 and block together provide a leg of substantially the same size as the leg 12 After the block is in position (Figures 14 and 15) the outer seams A between said block and the'leg I2 are welded so as to secure the parts securely together. When it is desired to replace a cutter I! for repair or for any other reason, it is only necessary tobreak the weld which is easily done since it is exposed. The block, axle and cutter are removed as a unit from the leg l2 and may be readily worked on. It is noted that in this form, the opening 25 which is provided in the leg l2 in Figures 1 to 9 is omitted. A pin 21', similar to the pin 21 but having a shorter shank, is inserted through v an opening 49 (Figure 1'7) in the bottom of the slot 46 of the block 45'. When the block is in position on the body It, the head of the pin 21' is engaged by the underside of the lug 41 on the leg I2, whereby the pin is-held against displacement. Manifestly with this form, the mounting and dismounting of the axle may be readily accomplished which permits the cutters to be repaired or replaced in the field and obviates the necessity of sending the bit to the shop for such replacement or repair.

What we claim and desire to secure by Letters Patent is:

1. A drill bit including, a body arranged to be connected to a drill stem, axles mounted directly on the .lower endof the body, a conical cutter having a bore mounted on each axle, each axle and bore having complementary recesses to fonn an elongate annular raceway therebetween, the body having an inclined opening therein adjacent each axle which opening registers with the annular recess, a plurality of elongate rollers insertable through said opening into each raceway for retaining the cutter on its axle, and a retaining pin fastened within the opening andv 75 depending into the raceway for preventing displacement of the rollers, said pin being arranged to engage the rollers without interfering with the rotation of the cutter.

2. A drill bit including, a body arranged to be connected to a. drill stem, axles mounted directly on the lower end of the body, a conical cutter having a bore mounted on each wherein the means to hold the rollers against axle, each axle and bore having complementary thereto.

recesses to form an elongate annular raceway therebetween, each axle and cutter having a circular opening above the raceway, elongate rollers 'insertable through said opening into each raceway-for retaining said cutter on the axle, and a retaining pin for each raceway fastened in the body and having a depending lug semi-circular in cross-section for engaging in the opening above the raceway to prevent displacement of the rollers without interfering with the rotation of the cutter on its axle.

3. A drill bit including a body formed for connectionwith a drill stem, axles carried by the body, cutters having bores to receive the axles, and elongated anti-friction rollers between the outer surfaces of the axles and the cutters and having semi-circular ends, the bores of the cutters and the adjacent parts of the outer surfaces of the axles being formed with complementary raceways having corresponding semi-circular ends to conformably receive said ends of the rollers, the cutters and body having alined open-.

ings, which in one position register with the adjacent ends of the raceways, the opening of the body extending therethrough whereby the rollers can be introduced longitudinally thereof through the openings and into the raceways, and closing means for the openings to hold the rollers against longitudinal movement out of the same.

4. A drill bit, in accordance with claim 3,

, 5. A drill bit including a body formed for connection with a drill stem, axles carried by the body, cutters having bores to receive the axles, and anti-friction rollers between the outer surfaces of the axles and the cutters and having semi-circular ends, the bore of the cutters and the adjacent parts of the outer surfaces of the axle being formed with complementary raceways having corresponding semi-circular ends, said ends of the rollers being conformably seated against the ends of the raceways whereby the cutter is connected to the body by the rollers, the rollers being elongated whereby to assume end thrusts throughout their said ends and also throughout their entire lengths, and likewise lateral thrusts throughout their entire lengths.

6. A drill bit in accordance with claim 5, wherein the body is formed to provide for introducing the rollers into the raceways, and means for retaining the rollers in the raceways in operative relation thereto.

7. A drill bit in accordance with claim 5, wherein the free end of the axle is reduced in diameter to provide shoulders spaced longitudinally of the axle, and wherein the said axle end and the body are formed with complementary tapered raceways, with tapered rollers conformably seated in the raceways and having squared ends for engagement with the respective shoulders.

' LEON L. SANDERS.

GEORGE C. STREET. 

